It is generally known that activated carbon sorbs many different types of chemicals. This versatile material, when activated, enjoys a variety of different uses based on this single characteristic, ranging from decolorizing solutions to sorbing toxic or noxious chemicals in gas mask filter elements.
Efforts have been made to develop fabric materials which can be used to make garments that protect the wearer against chemical weapon attack --i.e. which will sorb toxic chemicals that would otherwise be harmful if allowed to contact the wearer's skin. An additional desirable feature is that the fabric be air-permeable for comfort.
For example, U.S. Pat. No. 4,217,386 to Arons et al. discloses a laminated, sorbent carbon fabric comprising a central activated carbon fabric layer, spunbonded outer non-woven layers, and intermediate melt blown non-woven layers.
U.S. Pat. No. 3,769,144 to Economy et al. discloses a quilted fabric comprising a central layer of carbon fibers between outer layers of reinforcing fabric such as an aramid material called NOMEX (trademark of E.I. DuPont de Nemours).
Perhaps the most common material used to make chemical protective garments is based on a material comprising at least one layer of polypropylene infused with roughly 30% activated carbon, overlaid with polyurethane foam to form a foam-layer composite, and then sandwiched between cover layers of suitable fabric.
Although such a material does function to sorb toxic materials while remaining relatively air permeable, it suffers from a basic defect in that its use life is only on the order of from about 4 to 8 hours. At this point perspiration can work to saturate or greatly reduce the number of active sites on the carbon so that the garment no longer serves its primary purpose. Such a garment might well be unreliable after a relatively short exposure period in a war time situation where protracted or extended exposure of the wearer to airborne toxic chemicals would be possible, yet unpredictable. Clearly what is needed is a garment fabricated from a material which will maintain its capacity to sorb for much longer than just a fraction of a day.